Performance Evaluation of TCP with Adaptive Pacing and LRED in Multihop Wireless Networks

摘要

Transmission Control Protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless and Ad-hoc Networks can lead to TCP implementations with poor performance. In a wireless network, however packet losses occur more often due to unreliable wireless links than due to congestion. When using TCP over wireless links, each packet loss on the wireless link results in congestion control measures being invoked at the source. This causes severe performance degradation. If there is any packet loss in wireless networks, then the reason for that has to be found out. If there is congestion, then only congestion control mechanism has to be applied. This work shows the performance of TCP with Adaptive Pacing (TCP-AP) and Link Random Early Discard (LRED) as queuing model in multihop transmission when the source and destination nodes are in mobile nature. The adaptive pacing technique seeks to improve spatial reuse. The LRED technique seeks to react earlier to link overload. This paper consists of simulated environment results under different network scenarios. This work proves that the combination of TCP-AP and LRED give much better result than as the individual technique. Simulations are done with the use of NS-2.